Generator-motor

ABSTRACT

A generator-motor includes an alternator, electrode plates, a substrate, MOS transistors, and an MOS driver. Electrode plates are arranged on an end surface of the alternator so as to substantially form a U-shape to surround a rotation shaft of the alternator. MOS transistors are arranged on the electrode plate, while MOS transistors are arranged on the electrode plates respectively. The MOS driver is provided on the substrate arranged in a substantially U-shaped notch, and controls turn-on/off of the MOS transistors.

TECHNICAL FIELD

The present invention relates to a generator-motor including a controldevice on an end surface, and more particularly to a compactgenerator-motor.

BACKGROUND ART

Japanese Patent Laying-Open No. 2-266855 discloses a starter-generatorattaining a function as a three-phase motor starting an engine mountedon a vehicle and a function as a three-phase AC generator charging abattery.

Referring to FIG. 9, a starter-generator 300 disclosed in JapanesePatent Laying-Open No. 2-266855 includes a motor unit 301 and a driveunit 302. Motor unit 301 includes a stator and a rotor. Drive unit 302is provided on an end surface 301A of motor unit 301. Drive unit 302includes a cylindrical member 302A and a power module 302B. Power module302B is formed on a surface of cylindrical member 302A. That is, powermodule 302B is arranged in a direction perpendicular to a radialdirection 303 of cylindrical member 302A and in a longitudinal direction304 of a rotation shaft 301B of motor unit 301.

Power module 302B feeds a current to a coil included in motor unit 301and drives motor unit 301 so that the rotor outputs a prescribed torque.When the rotor in motor unit 301 rotates by rotation power of an engine,an AC voltage induced in three stators is converted to a DC voltage,whereby a battery is charged.

In this manner, power module 302B is provided on end surface 301A ofmotor unit 301, and drives motor unit 301 as a motor or a generator.

In the conventional starter-generator, however, the power module isarranged in a direction perpendicular to a radial direction when therotation shaft is assumed as a center and in a longitudinal direction ofthe rotation shaft. Accordingly, it is difficult to achieve smaller sizeof the starter-generator.

In particular, when a control circuit to control a generator installedin an engine is incorporated in the generator, a similar problem tendsto arise.

As Japanese Patent Laying-Open No. 2-266855 does not clearly disclose aposition where an electrode included in the power module is arranged, itis difficult to enhance efficiency in cooling the power module in theconventional starter-generator.

In addition, as Japanese Patent Laying-Open No. 2-266855 does notclearly disclose a position where a wire to the power module is arrangedeither, it is difficult to achieve shorter length and simplification ofthe wires in the conventional starter-generator.

DISCLOSURE OF THE INVENTION

From the foregoing, an object of the present invention is to provide acompact generator-motor.

Another object of the present invention is to provide a generator-motorincluding a control circuit occupying a smaller area.

Yet another object of the present invention is to provide agenerator-motor including a control device attaining high coolingefficiency.

Yet another object of the present invention is to provide agenerator-motor attaining shorter length and simplification of wires.

According to the present invention, a generator-motor includes a motorand a control device. The motor includes a rotor and a stator, andattains a function as a motor-generator. The control device is arrangedon an end surface of the motor so as to surround a rotation shaft of themotor, and controls drive of the motor.

Preferably, the control device includes a first electrode plate, asecond electrode plate, a third electrode plate, and a polyphaseswitching element group. The first, second and third electrode platesare arranged on the end surface of the motor so as to substantially forma U-shape to surround the rotation shaft of the motor. The polyphaseswitching element group controls a current supplied to the stator of themotor. The polyphase switching element group includes a plurality ofarms. The number of the arms corresponds to the number of phases of themotor, and each arm is constituted of first and second switchingelements. The first electrode plate is arranged in a position apart fromthe rotation shaft of the motor by a prescribed distance in a directionperpendicular to the rotation shaft. The second and third electrodeplates are arranged outside the first electrode plate. The first andsecond switching elements are connected electrically in series betweenthe first electrode plate and the third electrode plate. The pluralityof first switching elements are arranged on the first electrode plate,and the plurality of second switching elements are arranged on thesecond electrode plate.

Preferably, the control device further includes a control circuit. Thecontrol circuit controls a plurality of first and second switchingelements. The control circuit is provided on a ceramic substratearranged in a direction the same as an inplane direction of the first,second and third electrode plates in a substantially U-shaped notch.

Preferably, the control device further includes a plurality of firstwires and a plurality of second wires. The plurality of first wiresconnect the control circuit to the plurality of first switchingelements. The plurality of second wires connect the control circuit tothe plurality of second switching elements. The plurality of first wiresare arranged between the rotation shaft of the motor and the firstelectrode plate so as to surround the rotation shaft. The plurality ofsecond wires are arranged between the rotation shaft of the motor andthe first electrode plate and between the first electrode plate and themotor.

Preferably, the first and second electrode plates are arranged in afirst plane. The third electrode plate is arranged in a second planedifferent from the first plane.

Preferably, the second plane is closer to the motor than the first planeis.

Preferably, the plurality of arms are arranged radially in the inplanedirection of the first, second and third electrode plates.

Preferably, each of the plurality of first and second switching elementshas a control terminal, an input terminal, and an output terminal. Thecontrol terminal receives a control signal from the plurality of firstwires or the plurality of second wires. The input terminal receives adirect current. The output terminal outputs a direct current inaccordance with control contents by the control signal. The inputterminal of the first switching element is in contact with the firstelectrode plate. The control terminal of the first switching element isarranged on a side of the rotation shaft and connected to the firstwire. The output terminal of the first switching element is arranged ona side of the second electrode plate and connected to the secondelectrode plate. The input terminal of the second switching element isin contact with the second electrode plate. The control terminal of thesecond switching element is arranged on the side of the rotation shaftand connected to the second wire. The output terminal of the secondswitching element is arranged on a side of the third electrode plate andconnected to the third electrode plate.

Preferably, the control device includes a polyphase switching elementgroup, a control circuit, and first and second electrode plates. Thepolyphase switching element group controls a current supplied to astator. The control circuit controls the polyphase switching elementgroup. The first and second electrode plates are arranged on an endsurface of a motor so as to substantially form a U-shape to surround arotation shaft of the motor. The control circuit is provided on aceramic substrate arranged in a direction the same as an inplanedirection of the first and second electrode plates in a substantiallyU-shaped notch.

Preferably, the control circuit is resin-molded.

Preferably, the control device further includes a Zener diode. The Zenerdiode protects the polyphase switching element group against surge. TheZener diode is arranged in the notch.

Preferably, the control device further includes a capacitive element.The capacitive element smoothes a DC voltage from a DC power source andsupplies the smoothed DC voltage to the polyphase switching elementgroup. The capacitive element is arranged between the ceramic substrateand the second electrode plate.

Preferably, the control device further includes a field coil controlunit. The field coil control unit controls current feed to the fieldcoil different from the stator. The field coil control unit is arrangedon the ceramic substrate.

Preferably, a leadframe continuing to the first and second electrodeplates from the ceramic substrate and the first and second electrodeplates are provided in an identical plane.

In the generator-motor according to the present invention, the controldevice is arranged on the end surface of the motor in the directionperpendicular to the rotation shaft of the motor. Then, the controldevice controls drives of the motor.

Therefore, according to the present invention, the generator-motor canbe made smaller.

In addition, in the generator-motor according to the present invention,the first switching element constituting each arm is arranged on thefirst electrode plate arranged in an innermost portion in the endsurface of the motor, and the second switching element is arranged onthe second electrode plate arranged outside the first electrode plate.

Therefore, according to the present invention, the first and secondswitching elements can efficiently be cooled by an air flow introducedin the motor.

Moreover, in the generator-motor according to the present invention, thecontrol circuit controlling the first and second switching elements isarranged in a plane where the first, second and third electrode platesare present and in the notch in the first, second and third electrodeplates. The wire connecting the control circuit to the first switchingelement is arranged between the rotation shaft of the motor and thefirst electrode plate, and the wire connecting the control circuit tothe second switching element is arranged between the rotation shaft ofthe motor and the first electrode plate and between the first electrodeplate and the motor.

Therefore, according to the present invention, the wire can be shorterand simplified.

Furthermore, in the generator-motor according to the present invention,the control circuit controlling drive of the motor attaining a functionas the generator or the motor is arranged in a direction the same as theinplane direction of the first and second electrode plates arranged onthe end surface of the motor. The control circuit is arranged in thesubstantially U-shaped notch in the first and second electrode plates.

Therefore, according to the present invention, an area occupied by thecontrol circuit can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a generator-motor according to the presentinvention.

FIG. 2A is a plan view of an MOS transistor Tr1 shown in FIG. 1.

FIG. 2B is a cross-sectional view of MOS transistor Tr1 and electrodeplates 81, 82A.

FIG. 3 is a cross-sectional view along the line III-III shown in FIG. 1.

FIG. 4 is another cross-sectional view along the line III-III shown inFIG. 1.

FIG. 5 is a circuit block diagram of the generator-motor and a batteryshown in FIG. 1.

FIG. 6 is a schematic block diagram of an engine system including thegenerator-motor shown in FIG. 1.

FIG. 7 is another plan view of the generator-motor according to thepresent invention.

FIG. 8A is a plan view of an MOS transistor Tr1 shown in FIG. 7.

FIG. 8B is a cross-sectional view of MOS transistor Tr1 and electrodeplates 81, 82A.

FIG. 9 is a perspective view of a conventional starter-generator.

BEST MODES FOR CARRYING OUT THE INVENTION

In the following, embodiments of the present invention will be describedin detail with reference to the figures. It is noted that the samereference characters refer to the same or corresponding components inthe figures.

Referring to FIG. 1, a generator-motor 100 according to the presentinvention includes Zener diodes 21, DT1 to DT3, MOS transistors Tr1 toTr6, a power source 26, an MOS driver 27, an alternator 50, a custom IC70, electrode plates 81, 82A to 82C, 83, a substrate 84, terminals 84Ato 84D, and wires 85A to 85D, 86A to 86D.

Electrode plates 81, 82A to 82C, 83 and substrate 84 are formed on anend surface of alternator 50. Electrode plate 81 has a substantialU-shape, and is provided around a rotation shaft 50A of alternator 50.Electrode plates 82A to 82C are provided so as to substantially form aU-shape outside electrode plate 81 to surround electrode plate 81.Electrode plates 82A to 82C are arranged at prescribed intervals fromeach other. Electrode plate 83 is arranged in a position at a distancefrom rotation shaft 50A substantially the same as the distance betweenelectrode plates 82A-82C and rotation shaft 50A. A portion of electrodeplate 83 is arranged under electrode plates 82A to 82C. Substrate 84 isarranged in a direction the same as an inplane direction of electrodeplates 81, 82A to 82C, 83 in a substantially U-shaped notch in electrodeplate 81.

MOS transistors Tr1, Tr3, Tr5 are arranged on electrode plate 81, MOStransistor Tr2 and Zener diode DT1 are arranged on electrode plate 82A,MOS transistor Tr4 and Zener diode DT2 are arranged on electrode plate82B, and MOS transistor Tr6 and Zener diode DT3 are arranged onelectrode plate 82C.

MOS transistor Tr1 has the drain connected to electrode plate 81 and thesource connected to electrode plate 82A. MOS transistor Tr2 has thedrain connected to electrode plate 82A and the source connected toelectrode plate 83. Zener diode DT1 has one terminal connected toelectrode plate 82A and the other terminal connected to electrode plate83. Electrode plate 82A is connected to one end 51A of a U-phase coil ofalternator 50.

MOS transistor Tr3 has the drain connected to electrode plate 81 and thesource connected to electrode plate 82B. MOS transistor Tr4 has thedrain connected to electrode plate 82B and the source connected toelectrode plate 83. Zener diode DT2 has one terminal connected toelectrode plate 82B and the other terminal connected to electrode plate83. Electrode plate 82B is connected to one end 52A of a V-phase coil ofalternator 50.

MOS transistor Tr5 has the drain connected to electrode plate 81 and thesource connected to electrode plate 82C. MOS transistor Tr6 has thedrain connected to electrode plate 82C and the source connected toelectrode plate 83. Zener diode DT3 has one terminal connected toelectrode plate 82C and the other terminal connected to electrode plate83. Electrode plate 82C is connected to one end 53A of a W-phase coil ofalternator 50.

Therefore, MOS transistors Tr1, Tr2 are connected in series betweenelectrode plates 81 and 83 through electrode plate 82A. In addition, MOStransistors Tr3, Tr4 are connected in series between electrode plates 81and 83 through electrode plate 82B. Moreover, MOS transistors Tr5, Tr6are connected in series between electrode plates 81 and 83 throughelectrode plate 82C. Electrode plates 82A to 82C are connected to theU-phase coil, the V-phase coil and the W-phase coil of alternator 50,respectively.

MOS transistors Tr1, Tr2 constitute a U-phase arm, MOS transistors Tr3,Tr4 constitute a V-phase arm, and MOS transistors Tr5, Tr6 constitute aW-phase arm. The U-phase arm, the V-phase arm and the W-phase arm arearranged radially from rotation shaft 50A toward an outer circumferencein a plane perpendicular to rotation shaft 50A.

Substrate 84 is implemented by a ceramic substrate. Power supply 26,custom IC 70, MOS driver 27, and terminals 84A to 84D are arranged onsubstrate 84. Power supply 26, custom IC 70, and MOS driver 27 areresin-molded on substrate 84.

Terminal 84A receives a signal M/G and outputs the received signal M/Gto custom IC 70 through wire 85A. Terminal 84B receives a signal RLO,and outputs received signal RLO to custom IC 70 through wire 85B.Terminal 84C receives a signal CHGL, and outputs received signal CHGL tocustom IC 70 through wire 85C. Terminal 84D receives a DC voltage outputfrom a battery (not shown) and supplies the received DC voltage to powersupply 26 through wire 85D.

In wiring from substrate 84 to electrode plates 81, 82A to 82C, wires86A to 86F are arranged along a circumference surrounding rotation shaft50A in a space between rotation shaft 50A and electrode plate 81. Then,wire 86B is bent at a point C, and extends under electrode plate 81(between electrode plate 81 and alternator 50) to reach electrode plate82A. Wire 86D is bent at a point D, and extends under electrode plate 81(between electrode plate 81 and alternator 50) to reach electrode plate82B. In addition, wire 86F is bent at a point E, and extends underelectrode plate 81 (between electrode plate 81 and alternator 50) toreach electrode plate 82C.

Here, wires 86A, 86C, 86E constitute “a plurality of first wires,” andwires 86B, 86D, 86F constitute “a plurality of second wires.”

MOS driver 27 outputs a control signal to the gates of MOS transistorsTr1 to Tr6 through wires 86A to 86F, respectively.

Zener diode 21 is arranged in a space between substrate 84 and electrodeplates 81, 83, and connected between electrode plates 81 and 83. Acapacitor 22 is arranged in a space between substrate 84 and electrodeplates 81, 82C, 83, and connected between electrode plates 81 and 83.

Electrode plate 81 attains a function as a positive bus which will bedescribed later, and has one end connected to a terminal 87. Electrodeplate 81 receives a DC voltage output from the battery (not shown)through terminal 87. Electrode plate 83 attains a function as a negativebus which will be described later, and is connected to a ground node.

FIG. 2A is a plan view of MOS transistor Tr1, and FIG. 2B is across-sectional view of MOS transistor Tr1 and electrode plates 81, 82A.Referring to FIGS. 2A and 2B, MOS transistor Tr1 includes a gate G, asource S and a drain D. Gate G is connected to wire 86A. Source S isarranged adjacent to gate G, and connected to electrode plate 82A by awire GL. Therefore, in order to facilitate connection of gate G andsource S to wire 86A and electrode plate 82A through wire GL,respectively, MOS transistor Tr1 is arranged such that gate G isoriented to a side of rotation shaft 50A and source S is oriented to aside of electrode plate 82A. Drain D is connected to electrode plate 81.

Each of MOS transistors Tr2 to Tr6 includes a gate G, a source S and adrain D in a manner similar to MOS transistor Tr1, and arrangementthereof is also the same.

In a large power element such as MOS transistors Tr1 to Tr6, in manycases, gate G is provided in a central portion of one side along aperipheral portion of the element as described above, so that a lengthof a signal input line coming from the outside of the element isminimized and so that a pad for an output terminal is made as large aspossible.

Therefore, if drain D of MOS transistors Tr1 to Tr6 is provided on aback surface of the element, wire GL from source S is provided such thatit is drawn out of a side opposite to the side where gate G is present.

If MOS transistors Tr1 to Tr6 are arranged on electrode plates 81, 82A,82B, 82C, in order to attain a shorter length of wires 86A, 86B, 86C,86D, 86E, 86F, GL, MOS transistors Tr1 to Tr6 should be arranged suchthat gate G is oriented to the side of rotation shaft 50A and source Sis oriented to the outer circumferential side.

Then, MOS transistors Tr1, Tr3, Tr5 constitute an upper arm of aninverter controlling a current fed to a coil of each phase of alternator50, while MOS transistors Tr2, Tr4, Tr6 constitute a lower arm of theinverter controlling a current fed to a coil of each phase of alternator50. Accordingly, considering a direction of arrangement of MOStransistors Tr1 to Tr6, arranging electrode plate 81 in an innermostportion and arranging electrode plates 82A, 82B, 82C, 83 outsideelectrode plate 81 is optimal, from a viewpoint of improved efficiencyin cooling MOS transistors Tr1 to Tr6 (arranging MOS transistors Tr1 toTr6 in an inner portion on the end surface of alternator 50 serves tocool MOS transistors Tr1 to Tr6 by a flow of air sucked from outsideinto alternator 50) or a shorter length of wires 86A, 86B, 86C, 86D,86E, 86F, GL.

In addition, it is efficient to arrange electrode plate 83 on anoutermost side, because electrode plate 83 implements a negative bus andcan also be connected to a cover or a frame of alternator 50 forconnection to ground.

For these reasons, electrode plate 81 is arranged in the innermostportion, and electrode plates 82A, 82B, 82C, 83 are arranged outsideelectrode plate 81.

FIG. 3 shows a cross-sectional structure of alternator 50, viewed from across-section along the line III-III shown in FIG. 1. Referring to FIG.3, a rotor 55 is fixed to rotation shaft 50A, and a rotor coil 54 iswound around rotor 55. Stators 56, 57 are fixed on an outer side ofrotor 55, a U-phase coil 51 is wound around stator 56, and V-phase coil52 is wound around stator 57. In FIG. 3, the stator having a W-phasecoil wound is not shown.

Rotation shaft 50A has one end connected to a pulley 160, whichtransmits a torque generated by alternator 50 to a crank shaft of theengine or auxiliary machinery through a belt and in turn transmits therotation power of the crank shaft of the engine to rotation shaft 50A.

On the other end on a side opposite to one end of rotation shaft 50Aconnected to pulley 160, electrode plates 81, 83 are arranged so as tosurround rotation shaft 50A. A brush 58 is arranged so as to be incontact with rotation shaft 50A. Substrate 84 is provided above rotationshaft 50A, and capacitor 22 is arranged in front of substrate 84.

An MOS transistor 40 is provided on a side opposite to capacitor 22,with electrode plate 81 lying therebetween. MOS transistor 40 has thedrain connected to electrode plate 81 and the source connected to rotorcoil 54. When alternator 50 generates electric power, a power generationamount is determined depending on a rotor current flowing in rotor coil54. Therefore, MOS transistor 40 feeds rotor coil 54 with a rotorcurrent necessary for alternator 50 to generate an instructed amount ofelectric power.

In this manner, MOS transistor 40 controlling the rotor currentdetermining a power generation amount of alternator 50 is arranged on aback side of substrate 84 when viewed from a direction B.

FIG. 4 is a cross-sectional view showing an arrangement of electrodeplates 81, 82B, 82C, 83 and the like viewed from the cross-section alongthe line III-III shown in FIG. 1. Referring to FIG. 4, wires 86C, 86E,86F are arranged on the left of rotation shaft 50A, and electrode plates81, 82C, 83 are successively arranged toward an outer circumferentialside of wires 86C, 86E, 86F. Here, wires 86C, 86E, 86F and electrodeplates 81, 82C are arranged in an identical plane. Electrode plate 83 isarranged below wires 86C, 86E, 86F and electrode plates 81, 82C, andelectrode plate 83 partially overlaps with electrode plate 82C.

On the right of rotation shaft 50A, wire 86D and electrode plates 81,82B, 83 are successively arranged. A portion of wire 86D and electrodeplates 81, 82B are arranged in an identical plane. Electrode plate 83 isarranged below a portion of wire 86D and electrode plates 81, 82B, andelectrode plate 83 partially overlaps with electrode plate 82B. MOStransistor Tr4 is arranged on electrode plate 82B. Wire 86D is arrangedbetween rotation shaft 50A and electrode plate 81 so as to surroundrotation shaft 50A until it reaches point D (see FIG. 1). After wire 86Dis bent at point D, it extends under electrode plate 81 and is connectedto the gate of MOS transistor Tr4.

In this manner, electrode plate 83 is arranged below the plane whereelectrode plates 81, 82B, 82C are arranged, that is, on a side closer tothe alternator.

FIG. 5 is a circuit block diagram of generator-motor 100 and a battery10. A control circuit 20 includes Zener diode 21 arranged betweensubstrate 84 and electrode plates 81, 83, capacitor 22 arranged betweensubstrate 84 and electrode plates 81, 82C, 83, MOS transistors Tr1, Tr3,Tr5 arranged on electrode plate 81, MOS transistors Tr2, Tr4, Tr6arranged on electrode plates 82A to 82C respectively, power source 26arranged on substrate 84, MOS driver 27, custom IC 70, MOS transistor40, and a diode 41.

MOS transistors Tr1, Tr2 constitute a U-phase arm 23, MOS transistorsTr3, Tr4 constitute a V-phase arm 24, and MOS transistors Tr5, Tr6constitute a W-phase arm 25.

Custom IC 70 is constituted of a synchronous rectifier 28 and controlunits 29, 30. A rotation angle sensor 60 is contained in alternator 50.

Alternator 50 includes U-phase coil 51, V-phase coil 52, W-phase coil53, and rotor coil 54. U-phase coil 51 has one end 51A connected to anode N1 between MOS transistor Tr1 and MOS transistor Tr2. V-phase coil52 has one end 52A connected to a node N2 between MOS transistor Tr3 andMOS transistor Tr4. W-phase coil 53 has one end 53A connected to a nodeN3 between MOS transistor Tr5 and MOS transistor Tr6.

A fuse FU1 is connected between a positive electrode of battery 10 andcontrol circuit 20. That is, fuse FU1 is arranged on a side of battery10, rather than a side of Zener diode 21. In this manner, by arrangingfuse FU1 on the side of battery 10 rather than the side of Zener diode21, detection of overcurrent is no longer necessary and control circuit20 can be reduced in size. A fuse FU2 is connected between the positiveelectrode of battery 10 and power source 26.

Zener diode 21 and capacitor 22 are connected in parallel between apositive bus L1 and a negative bus L2.

U-phase arm 23, V-phase arm 24, and W-phase arm 25 are connected inparallel between positive bus L1 and negative bus L2. Zener diode DT1 isconnected in parallel to MOS transistor Tr2 between node N1 and negativebus L2. Zener diode DT2 is connected in parallel to MOS transistor Tr4between node N2 and negative bus L2. Zener diode DT3 is connected inparallel to MOS transistor Tr6 between node N3 and negative bus L2.

MOS transistor 40 is connected between the positive electrode of battery10 and a node N4. Diode 41 is connected between node N4 and a groundnode GND.

Here, diodes connected in parallel to MOS transistors Tr1 to Tr6, 40respectively are parasitic diodes formed between MOS transistors Tr1 toTr6, 40 and a semiconductor substrate respectively.

Battery 10 outputs, for example, a DC voltage of 12V. Zener diode 21absorbs a surge voltage generated between positive bus L1 and negativebus L2. In other words, Zener diode 21 absorbs a surge voltage when thesurge voltage not smaller than a prescribed voltage level is appliedbetween positive bus L1 and negative bus L2, and lowers the DC voltageapplied to capacitor 22 and MOS transistors Tr1 to Tr6 to a level notlarger than the prescribed voltage level. Therefore, it is not necessaryto secure large capacitance of capacitor 22 and large size of MOStransistors Tr1 to Tr6, considering the surge voltage. As a result,capacitor 22 and MOS transistors Tr1 to Tr6 can be reduced in size.

Capacitor 22 smoothes an input DC voltage, and supplies the smoothed DCvoltage to U-phase arm 23, V-phase arm 24, and W-phase arm 25. MOStransistors Tr1 to Tr6 receive a control signal from MOS driver 27 atthe gates, and are turned on/off in accordance with the received controlsignal. Then, MOS transistors Tr1 to Tr6 switch the direct currentflowing in U-phase coil 51, V-phase coil 52, and W-phase coil 53 ofalternator 50 by the DC voltage supplied from capacitor 22, so as todrive alternator 50. In addition, MOS transistors Tr1 to Tr6 convert anAC voltage generated by U-phase coil 51, V-phase coil 52, and W-phasecoil 53 of alternator 50 to the DC voltage in accordance with thecontrol signal from MOS driver 27, so as to charge battery 10.

Zener diodes DT1 to DT3 prevent application of overvoltage to MOStransistors Tr2, Tr4, Tr6 when U-phase coil 51, V-phase coil 52, andW-phase coil 53 of alternator 50 generate electric power, respectively.In other words, Zener diodes DT1 to DT3 protect the lower arm of U-phasearm 23, V-phase arm 24, and W-phase arm 25 when alternator 50 is in apower generation mode.

Power source 26 receives the DC voltage output from battery 10 throughfuse FU2, and supplies the received DC voltage to MOS driver 27 as twoDC voltages having different voltage levels. More specifically, powersource 26 generates, for example, a DC voltage of 5V based on the DCvoltage of 12V received from battery 10, and supplies to MOS driver 27the generated DC voltage of 5V and the DC voltage of 12V received frombattery 10.

MOS driver 27 is driven by the DC voltages of 5V and 12V supplied frompower source 26. Then, MOS driver 27 generates a control signal forturning on/off MOS transistors Tr1 to Tr6 in synchronization with asynchronization signal from synchronous rectifier 28, and outputs thegenerated control signal to the gates of MOS transistors Tr1 to Tr6.More specifically, MOS driver 27 generates the control signal forturning on/off MOS transistors Tr1 to Tr6 in the power generation modeof alternator 50 based on synchronization signals SYNG1 to SYNG6 fromsynchronous rectifier 28, and generates the control signal for turningon/off MOS transistors Tr1 to Tr6 in a drive mode of alternator 50 basedon synchronization signals SYNM1 to SYNM6 from synchronous rectifier 28.

Upon receiving a signal GS from control unit 30, synchronous rectifier28 generates synchronization signals SYNG1 to SYNG6 based on timingsignals TG1 to TG6 from control unit 29, and outputs generatedsynchronization signals SYNG1 to SYNG6 to MOS driver 27. In addition,upon receiving a signal MS from control unit 30, synchronous rectifier28 generates synchronization signals SYNM1 to SYNM6 based on timingsignals TM1 to TM6 from control unit 29, and outputs generatedsynchronization signals SYNM1 to SYNM6 to MOS driver 27.

Control unit 29 receives angles θ1, θ2, θ3 from rotation angle sensor60, and detects the number of revolutions MRN of rotor 55 included inalternator 50 based on received angles θ1, θ2, θ3.

Angle θ1 represents an angle between a direction of magnetic forcegenerated by U-phase coil 51 and a direction of magnetic force generatedby rotor coil 54. Angle θ2 represents an angle between a direction ofmagnetic force generated by V-phase coil 52 and a direction of magneticforce generated by rotor coil 54. Angle θ3 represents an angle between adirection of magnetic force generated by W-phase coil 53 and a directionof magnetic force generated by rotor coil 54. Angles θ1, θ2, θ3periodically vary in a range from 0° to 360°. Therefore, control unit 29detects the number of revolutions that periodically varies in aprescribed time period in a range from 0° to 360°, so as to obtain thenumber of revolutions MRN.

Then, control unit 29 detects a timing of voltages Vui, Vvi, Vwi inducedin U-phase coil 51, V-phase coil 52, and W-phase coil 53 of alternator50 based on angles θ1, θ2, θ3, and generates timing signals TG1 to TG6indicating a timing of turn-on/off of MOS transistors Tr1 to Tr6 forconverting voltages Vui, Vvi, Vwi induced in U-phase coil 51, V-phasecoil 52, and W-phase coil 53 to DC voltages based on that detectedtiming.

In addition, control unit 29 generates timing signals TM1 to TM6indicating a timing of turn-on/off of MOS transistors Tr1 to Tr6 forcausing alternator 50 to operate as a drive motor, based on angles θ1,θ2, θ3 and the detected number of revolutions MRN.

Then, control unit 29 outputs generated timing signals TG1 to TG6, TM1to TM6 to synchronous rectifier 28.

Control unit 30 receives signal M/G, signal RLO, and signal CHGL from anexternally provided eco-run ECU (Electrical Control unit) (which will bedescribed later). In addition, control unit 30 receives voltages Vu, Vv,Vw applied to U-phase coil 51, V-phase coil 52, and W-phase coil 53 ofalternator 50.

Control unit 30 determines whether alternator 50 is to operate as agenerator or a drive motor, based on signal M/G. When control unit 30determines that alternator 50 is to operate as the generator, controlunit 30 generates and outputs signal GS to synchronous rectifier 28. Onthe other hand, when control unit 30 determines that alternator 50 is tooperate as the drive motor, control unit 30 determines a manner ofcurrent feed to U-phase coil 51, V-phase coil 52, and W-phase coil 53based on voltages Vu, Vv, Vw, and generates signal MS for drivingalternator 50 in accordance with the determined current feeding manner,for output to synchronous rectifier 28.

In addition, control unit 30 calculates a rotor current in order foralternator 50 to generate an instructed amount of electric power, basedon signal RLO. Control unit 30 generates a signal RCT for feeding thecalculated rotor current to rotor coil 54, and outputs the generatedsignal to the gate of MOS transistor 40.

Moreover, control unit 30 provides temperature information of MOStransistor 40 to outside in a signal format, based on signal CHGL.

MOS transistor 40 sets the rotor current supplied from battery 10 torotor coil 54 to a prescribed value, based on signal RCT from controlunit 30. Here, diode 41 serves as a free wheel diode in controllingturning-off of the rotor.

Alternator 50 operates either as the drive motor or as the generator.Alternator 50 generates a prescribed torque under the control of controlcircuit 20 at the start of the engine in the drive mode where itoperates as the drive motor, and starts the engine using the generatedprescribed torque. In addition, alternator 50 drives auxiliary machineryusing the generated torque during a period except for start of theengine.

Moreover, alternator 50 generates an AC voltage in accordance with therotor current flowing in rotor coil 54 in the power generation modewhere it operates as the generator, and supplies the generated ACvoltage to U-phase arm 23, V-phase arm 24, and W-phase arm 25.

Rotation angle sensor 60 detects angles θ1, θ2, θ3, and outputs detectedangles θ1, θ2, θ3 to control unit 29.

An overall operation in generator-motor 100 will now be described.Control unit 30 determines whether alternator 50 is to operate as agenerator or a drive motor, based on signal M/G from the eco-run ECU.When control unit 30 determines that alternator 50 is to operate as thegenerator, control unit 30 generates and outputs signal GS tosynchronous rectifier 28. Control unit 30 generates signal RCT based onsignal RLO from the eco-run ECU, and outputs the generated signal to thegate of MOS transistor 40.

Then, MOS transistor 40 switches the rotor current supplied from battery10 to rotor coil 54 in response to signal RCT. Rotor 55 of alternator 50is rotated by the rotation power of the engine. Then, alternator 50generates a designated amount of electric power and supplies theelectric power to U-phase arm 23, V-phase arm 24, and W-phase arm 25.

On the other hand, upon receiving angles θ1, θ2, θ3 from rotation anglesensor 60, control unit 29 generates timing signals TG1 to TG6, TM1 toTM6 with the method described above based on received angles θ1, θ2, θ3,and outputs the generated timing signal to synchronous rectifier 28.

Synchronous rectifier 28 generates synchronization signals SYNG1 toSYNG6 in synchronization with timing signals TG1 to TG6 based on signalGS from control unit 30, and outputs the same to MOS driver 27. MOSdriver 27 generates the control signal for turning on/off MOStransistors Tr1 to Tr6 in synchronization with synchronization signalsSYNG1 to SYNG6, and outputs the control signal to the gates of MOStransistors Tr1 to Tr6.

Then, MOS transistors Tr1 to Tr6 are turned on/off by the control signalfrom MOS driver 27, and converts the AC voltage generated by alternator50 to the DC voltage, so as to charge battery 10.

Here, Zener diodes DT1 to DT3 absorb a surge voltage even if the surgevoltage is superposed on the AC voltage generated by alternator 50. Inother words, Zener diodes DT1 to DT3 prevent application of a voltageexceeding a withstand voltage to MOS transistors Tr2, Tr4, Tr6. Inaddition, Zener diode 21 absorbs a surge voltage even if the surgevoltage is superposed on the DC voltage between positive bus L1 andnegative bus L2. In other words, Zener diode 21 prevents application ofa voltage exceeding a withstand voltage to MOS transistors Tr1, Tr3,Tr5.

When control unit 30 determines that alternator 50 is to be driven asthe drive motor based on signal M/G, control unit 30 determines a mannerof current feed to U-phase arm 23, V-phase arm 24, and W-phase arm 25based on voltages Vu, Vv, Vw, and generates signal MS for drivingalternator 50 in accordance with the determined current feeding manner,for output to synchronous rectifier 28.

Upon receiving angles θ1, θ2, θ3 from rotation angle sensor 60, controlunit 29 generates timing signals TG1 to TG6, TM1 to TM6 with the methoddescribed above based on received angles θ1, θ2, θ3, and outputs thegenerated timing signal to synchronous rectifier 28.

Synchronous rectifier 28 generates synchronization signals SYNM1 toSYNM6 in synchronization with timing signals TM1 to TM6 based on signalMS from control unit 30, and outputs the same to MOS driver 27. MOSdriver 27 generates the control signal for turning on/off MOStransistors Tr1 to Tr6 in synchronization with synchronization signalsSYNM1 to SYNM6, and outputs the same to the gates of MOS transistors Tr1to Tr6.

Then, MOS transistors Tr1 to Tr6 are turned on/off by the control signalfrom MOS driver 27, and switches the current supplied to U-phase arm 23,V-phase arm 24, and W-phase arm 25 of alternator 50 from battery 10 soas to drive alternator 50 as the drive motor. In this manner, alternator50 supplies a prescribed torque to a crank shaft of the engine at thestart of the engine. In addition, alternator 50 supplies a prescribedtorque to the auxiliary machinery.

Here, Zener diode 21 absorbs a surge voltage generated between positivebus L1 and negative bus L2 by turning-on/off of MOS transistors Tr1 toTr6. In other words, Zener diode 21 prevents application of a voltageexceeding a withstand voltage to MOS transistors Tr1, Tr3, Tr5. Inaddition, Zener diodes DT1 to DT3 absorb a surge voltage even if MOStransistors Tr1, Tr3, Tr5 are turned off and the surge voltage isapplied to MOS transistors Tr2, Tr4, Tr6. In other words, Zener diodesDT1 to DT3 prevent application of a voltage exceeding a withstandvoltage to MOS transistors Tr2, Tr4, Tr6.

As described above, MOS transistors Tr1 to Tr6 are arranged on electrodeplates 81, 82A to 82C provided on the end surface of alternator 50. Suchan arrangement is allowed because application of overvoltage to MOStransistors Tr1 to Tr6 is prevented and MOS transistors Tr1 to Tr6 arereduced in size by providing Zener diodes 21, DT1 to DT3. In particular,as one Zener diode 21 protects three MOS transistors Tr1, Tr3, Tr5,Zener diode 21 protecting three MOS transistors Tr1, Tr3, Tr5 can bearranged utilizing a space between substrate 84 and electrode plates 81,83.

In addition, as Zener diode 21 also prevents application of overvoltageto capacitor 22, a capacitance of capacitor 22 can be reduced.Consequently, capacitor 22 can be arranged in a space between substrate84 and electrode plates 81, 82C, 83.

By virtue of these factors, overall control circuit 20 is reduced insize, and control circuit 20 can be arranged on the end surface ofalternator 50. In other words, control circuit 20 can be arranged in aplane perpendicular to rotation shaft 50A, instead of in thelongitudinal direction of rotation shaft 50A of alternator 50. As aresult, an area occupied by control circuit 20 can be reduced.

Electrode plate 81 is arranged in the innermost portion, and electrodeplates 82A, 82B, 82C, 83 are arranged outside electrode plate 81. Eachof MOS transistors Tr1 to Tr6 is arranged on electrode plates 81, 82A,82B, 82C such that gate G is oriented to the side of rotation shaft 50Aand source S is oriented to the outer circumferential side.

Therefore, MOS transistors Tr1 to Tr6 are arranged in the inner portionon the end surface of alternator 50, so that efficiency in cooling MOStransistors Tr1 to Tr6 by means of a flow of air sucked from outsideinto alternator 50 can be enhanced. In addition, wires 86A, 86B, 86C,86D, 86E, 86F can have shorter length and be simplified.

FIG. 6 shows a block diagram of an engine system 200 includinggenerator-motor 100. Referring to FIG. 6, engine system 200 includesbattery 10, control circuit 20, alternator 50, an engine 110, a torqueconverter 120, an automatic transmission 130, pulleys 140, 150, 160, anelectromagnetic clutch 140 a, a belt 170, auxiliary machinery 172, astarter 174, an electrohydraulic pump 180, a fuel injection valve 190,an electric motor 210, a throttle valve 220, an eco-run ECU 230, anengine ECU 240, and a VSC (Vehicle Stability Control)-ECU 250.

Alternator 50 is arranged proximate to engine 110. Control circuit 20 isarranged on the end surface of alternator 50, as described above.

Engine 110 is started by alternator 50 or starter 174, and generates aprescribed output power. More specifically, engine 110 is started byalternator 50 at a start after stop in accordance with an economyrunning system (also referred to as “eco-run”, “idle stop”, “idlingstop”), while engine 110 is started by starter 174 at a start using anignition key. Engine 110 provides the generated output power from acrank shaft 110 a to torque converter 120 or pulley 140.

Torque converter 120 transmits the rotation power of engine 110 fromcrank shaft 110 a to automatic transmission 130. Automatic transmission130 attains a function of automatic transmission control, sets thetorque from torque converter 120 to a torque in accordance withtransmission control, and provides the torque to an output shaft 130 a.

Pulley 140 contains electromagnetic clutch 140 a, through which pulley140 is connected to crank shaft 110 a of engine 110. Pulley 140 operatestogether with pulleys 150, 160 via belt 170.

Electromagnetic clutch 140 a is turned on/off under the control ofeco-run ECU 230, and connects/disconnects pulley 140 to/from crank shaft110 a. Belt 170 links pulleys 140, 150, 160 with one another. Pulley 150is connected to a rotation shaft of auxiliary machinery 172.

Pulley 160 is connected to rotation shaft 50A of alternator 50, andturned by crank shaft 10 a of engine 110 or alternator 50.

Auxiliary machinery 172 is implemented by one or more of a compressorfor air-conditioner, a power steering pump, and an engine-cooling waterpump. Auxiliary machinery 172 receives the output power from alternator50 through pulley 160, belt 170 and pulley 150, and is driven by thereceived output power.

Alternator 50 is driven by control circuit 20. Alternator 50 receivesthe rotation power of crank shaft 110 a of engine 110 through pulley140, belt 170 and pulley 160, and converts the received rotation powerto electric energy. In other words, alternator 50 generates electricpower by the rotation power of crank shaft 110 a. Here, alternator 50generates electric power in the following two cases. That is, alternator50 generates electric power when it receives the rotation power of crankshaft 110 a produced by drive of engine 110 in a normal running state ofa hybrid vehicle equipped with engine system 200. In addition, thoughengine 110 is not driven, alternator 50 generates electric power uponreceiving the rotation power transmitted to crank shaft 110 a fromdriving wheels in deceleration of the hybrid vehicle.

Alternator 50 is driven by control circuit 20, and outputs a prescribedoutput power to pulley 160. The prescribed output power is transmittedto crank shaft 110 a of engine 110 through belt 170 and pulley 140 whenengine 110 is started, or it is transmitted to auxiliary machinery 172through belt 170 and pulley 150 in driving auxiliary machinery 172.

Battery 10 supplies the DC voltage of 12V to control circuit 20, asdescribed above.

Control circuit 20 converts the DC voltage from battery 10 to the ACvoltage under the control of eco-run ECU 230 as described above, anddrives alternator 50 using the obtained AC voltage. In addition, controlcircuit 20 converts the AC voltage generated by alternator 50 to the DCvoltage under the control of eco-run ECU 230, and charges battery 10using the obtained DC voltage.

Starter 174 starts engine 110 under the control of eco-run ECU 230.Electrohydraulic pump 180 is contained in automatic transmission 130,and supplies a hydraulic fluid to a hydraulic control unit provided inautomatic transmission 130 under the control of engine ECU 240. Thehydraulic fluid serves to adjust an actuation state of a clutch, a brakeand a one-way clutch within automatic transmission 130 by means of acontrol valve in the hydraulic control unit, so as to switch a shiftstate as required.

Eco-run ECU 230 serves for switching on/off of electromagnetic clutch140 a, mode control of alternator 50 and control circuit 20, control ofstarter 174, and control of an amount of power storage in battery 10.Here, the mode control of alternator 50 and control circuit 20 refers tocontrol of the power generation mode in which alternator 50 attains afunction as the generator and the drive mode in which alternator 50attains a function as the drive motor. Eco-run ECU 230 generates signalM/G for controlling the power generation mode and the drive mode, andoutputs the signal to control circuit 20. Here, a control line fromeco-run ECU 230 to battery 10 is not shown.

In addition, eco-run ECU 230 detects the number of revolutions MRN basedon angles θ1, θ2, θ3 from rotation angle sensor 60 contained inalternator 50, whether or not the eco-run system has been started by adriver from an eco-run switch, and other data.

Fuel injection valve 190 controls injection of a fuel under the controlof engine ECU 240. Electric motor 210 controls an opening position ofthrottle valve 220 under the control of engine ECU 240. Throttle valve220 is set to a prescribed opening position by electric motor 210.

Engine ECU 240 serves for control of turn-on/off of auxiliary machinery172 except for the engine-cooling water pump, control of drive ofelectrohydraulic pump 180, transmission control of automatictransmission 130, control of injection of a fuel by fuel injection valve190, control of an opening position of throttle valve 220 by electricmotor 210, and other engine control.

In addition, engine ECU 240 detects a temperature of engine-coolingwater from a temperature sensor, whether or not an accelerator pedal hasbeen pressed down from an idle switch, a degree of press-down of theaccelerator from an accelerator press-down degree sensor, a steeringwheel angle from a steering wheel angle sensor, a vehicle speed from avehicle speed sensor, a throttle opening position from a throttleopening position sensor, a shift position from a shift position sensor,the number of revolutions of the engine from an engine speed sensor,whether or not an operation to turn on/off of the air-conditioner hasbeen performed from a switch of the air-conditioner, and other data.

VSC-ECU 250 detects whether or not a brake pedal has been pressed downfrom a brake switch, and other data.

Eco-run ECU 230, engine ECU 240 and VSC-ECU 250 mainly include amicrocomputer, in which a CPU (Central Processing Unit) executes anecessary operation in accordance with a program written in an internalROM (Read Only Memory) and a variety of types of control are appliedbased on a result of the operation. The result of the operation anddetected data can be communicated as data, among eco-run ECU 230, engineECU 240 and VSC-ECU 250. Therefore, the data can be exchanged asrequired, and control can be applied in a cooperative manner.

An operation of engine system 200 will now be described. Eco-run ECU 230is responsible for an automatic stop processing, a motor driveprocessing during engine stop, an automatic start processing, amotor-driven start processing, a motor control processing duringrunning, and a motor control processing during deceleration.

First, the automatic stop processing will be described. Engine ECU 240receives an engine-cooling water temperature THW, an idle switch, abattery voltage, a brake switch, a vehicle speed SPD, and the like.Then, engine ECU 240 detects whether or not the accelerator pedal hasbeen pressed down from the idle switch, and whether or not the brakepedal has been pressed down from the brake switch.

When the automatic stop processing is started, engine-cooling watertemperature THW, whether or not the accelerator pedal has been presseddown, a voltage of battery 10, whether or not the brake pedal has beenpressed down, vehicle speed SPD, and the like are read in a work area ofan RAM (Random Access Memory) within eco-run ECU 230. Eco-run ECU 230determines whether or not a condition for automatic stop is satisfiedbased on such data. Here, the condition for automatic stop is satisfiedif all of the following conditions are met: for example, engine-coolingwater temperature THW is within a range from a lower limit to an upperlimit; vehicle speed SPD is 0 km/h; and the like.

When eco-run ECU 230 determines that the condition for automatic stop issatisfied, eco-run ECU 230 performs an engine stop processing. Morespecifically, eco-run ECU 230 instructs cutting-off of fuel supply toengine ECU 240. Engine ECU 240 controls fuel injection valve 190 to stopfuel injection in response to the instruction of cutting-off of fuelsupply, so as to completely close throttle valve 220. In this manner,fuel injection valve 190 stops fuel injection, combustion in acombustion chamber of engine 110 is stopped, and the operation of engine110 is stopped.

The motor drive processing during engine stop will now be described.When the motor drive processing during engine stop is started, eco-runECU 230 controls control circuit 20 so as to turn on electromagneticclutch 140 a, to set the number of revolutions of alternator 50 to thetarget number of revolutions during idle, and to drive alternator 50.More specifically, eco-run ECU 230 outputs signal M/G for causingalternator 50 to operate as the drive motor to control circuit 20. Then,control circuit 20 causes alternator 50 to operate as the drive motorwith the method described above based on signal M/G from eco-run ECU230, and drives alternator 50 such that the number of revolutionsthereof attains the target number of revolutions during idle. In thismanner, rotation shaft 50A of alternator 50 rotates and pulley 160 alsorotates.

The rotation power transmitted to pulley 160 is transmitted to crankshaft 110 a through belt 170 and pulley 140, so that crank shaft 110 arotates at the target number of revolutions during idle. Then, eco-runECU 230 confirms that a state in which engine 110 rotates at the targetnumber of revolutions during idle is maintained for a certain period oftime.

In this manner, while engine 110 is stopped, the output power fromalternator 50 rotates engine 110 at the number of revolutions equivalentto that during idle. Accordingly, a pressure in a cylinder of engine 110having throttle valve 220 completely closed can sufficiently be lowered.In addition, a difference of a load torque between operation steps ofengine 110 in which combustion does not take place is made smaller, andvariation in the torque during rotation can be reduced. As a result,rocking at the time of stop can be suppressed, and a driver will notfeel uncomfortable when engine 110 automatically stops.

Thereafter, eco-run ECU 230 determines whether or not a request to driveauxiliary machinery 172 has been issued. If eco-run ECU 230 determinesthat the request to drive auxiliary machinery 172 has been issued, itturns off electromagnetic clutch 140 a, and sets alternator 50 to thedrive mode. In this case as well, alternator 50 is caused to rotate atthe target number of revolutions during idle by the operation describedabove, and its rotation power is transmitted to auxiliary machinery 172through pulley 160, belt 170 and pulley 150.

The compressor for the air-conditioner and the power steering pump arethus driven. Here, as electromagnetic clutch 140 a is turned off, crankshaft 110 a of engine 110 does not rotate, thereby preventing waste ofelectric power and improving fuel efficiency.

In this manner, eco-run ECU 230 drives alternator 50 while engine 110 isstopped and rotates crank shaft 110 a of engine 110 so as to perform aprocessing for reducing rocking, or drives auxiliary machinery 172.

The automatic start processing will now be described. When the automaticstart processing is started, eco-run ECU 230 determines whether or not acondition for automatic start is satisfied by reading data the same asthat read for the automatic stop processing. More specifically, eco-runECU 230 determines that the condition for automatic start is satisfiedif one of the conditions for automatic start is not satisfied.

Then, eco-run ECU 230 stops the motor drive processing during enginestop when it determines that the condition for automatic start is met.The automatic start processing is thus completed.

The motor-driven start processing will now be described. When themotor-driven start processing is started, eco-run ECU 230 issues aninstruction to prohibit turn-on of the air-conditioner to engine ECU240. Then, engine ECU 240 stops driving of the air-conditioner if theair-conditioner has been turned on. Load imposed in alternator 50 canthus be mitigated.

Then, eco-run ECU 230 turns on electromagnetic clutch 140 a, and setsalternator 50 to the drive mode. Here, with the same operation asdescribed above, the rotation power of alternator 50 is transmitted tocrank shaft 110 a through pulley 160, belt 170 and pulley 140, so thatcrank shaft 110 a is rotated at the target number of revolutions duringidle.

Thereafter, eco-run ECU 230 determines whether or not the number ofrevolutions of engine 110 attains the target number of revolutionsduring idle. If the number of revolutions of engine 110 attains thetarget number of revolutions during idle, eco-run ECU 230 issues aninstruction to start fuel injection to engine ECU 240. Then, engine ECU240 controls fuel injection valve 190 so as to inject fuel, and fuelinjection valve 190 starts injection of the fuel. Engine 110 is thusstarted and starts its operation.

Here, engine 110 is quickly started because the fuel injection isstarted after the target number of revolutions during idle has beenattained. In addition, engine 110 attains stable number of revolutionsin a short period of time. Moreover, as crank shaft 110 a of engine 110is rotated by the output power from alternator 50 until fuel injectionis started, the vehicle can start to move by a creep force generated bytorque converter 120 in a non-lockup state, provided that the torqueoutput from alternator 50 is sufficiently high.

In this manner, in the motor-driven start processing, alternator 50 isdriven in the drive mode.

The motor control processing during running will now be described. Whenthe motor control processing during running is started, eco-run ECU 230determines whether or not start of engine 110 has been completed by themotor-driven start processing. If eco-run ECU 230 determines that thestart of engine 110 has been completed, the motor-driven startprocessing is stopped. Then, eco-run ECU 230 issues an instruction topermit turning-on of the air-conditioner to engine ECU 240. In response,engine ECU 240 makes a switch such that the compressor for theair-conditioner operates together with rotation of pulley 150 if the airconditioner has been turned on, so as to allow drive of theair-conditioner.

Thereafter, eco-run ECU 230 determines whether or not the vehicle is indeceleration. Here, deceleration refers, for example, to a state inwhich the accelerator pedal has completely returned to its originalposition during running, that is, the idle switch has been turned onduring running. Therefore, eco-run ECU 230 determines that the vehicleis not in deceleration if the idle switch is turned off Then, eco-runECU 230 turns on electromagnetic clutch 140 a and sets alternator 50 tothe power generation mode. More specifically, eco-run ECU 230 outputssignal M/G for causing alternator 50 to operate in the power generationmode to control circuit 20. Then, control circuit 20 drives alternator50 in the power generation mode with the method described above, inresponse to signal M/G from eco-run ECU 230.

Then, the rotation power of crank shaft 110 a of engine 110 istransmitted to the rotation shaft of alternator 50 through pulley 140,belt 170 and pulley 160. Alternator 50 generates electric power, andoutputs the AC voltage to control circuit 20. Control circuit 20converts the AC voltage to the DC voltage in accordance with control ofeco-run ECU 230, so as to charge battery 10. The motor controlprocessing during running is thus completed.

In this manner, during normal running, alternator 50 is driven in thepower generation mode, and the rotation power of engine 110 is convertedto electric energy.

On the other hand, if eco-run ECU 230 determines that the vehicle is indeceleration, the motor control processing during deceleration isperformed. Finally, the motor control processing during decelerationwill be described. When the motor control processing during decelerationis started, eco-run ECU 230 determines whether or not cutting-off offuel supply in deceleration has been completed. Under a conditiondetermined as deceleration, fuel injection to engine 110 is stopped by aprocessing to cut off fuel supply during deceleration by engine ECU 240,until the number of revolutions of engine 110 is lowered to attain therecovery reference number of revolutions for determining return to fuelinjection (that is, the target number of revolutions during idle).

If the number of revolutions of engine 110 is lowered to the recoveryreference number of revolutions, torque converter 120 is switched from alockup state to the non-lockup state and fuel injection is resumed, soas to prevent engine stall due to fall of the number of revolutions ofthe engine.

If the fuel is being cut off during deceleration, eco-run ECU 230 turnson electromagnetic clutch 140 a, and sets alternator 50 to electricpower generation at a power generation voltage higher than a normalpower generation voltage. Accordingly, even if engine 110 is notoperated, crank shaft 110 a of engine 110 is rotated by rotation ofwheels, and rotation of crank shaft 110 a is transmitted to alternator50 through pulley 140, belt 170 and pulley 160. Alternator 50 generatesthe AC voltage. Therefore, energy generated by running of a vehicle isrecovered as electric power. In other words, the power generation modeof alternator 50 here is comparable to a regenerative mode.

When the number of revolutions of engine is lowered to the recoveryreference number of revolutions, engine ECU 240 ends the processing tocut off the fuel supply. Then, eco-run ECU 230 determines whether or notthe number of revolutions of the engine is smaller than the engine stallreference number of revolutions. The engine stall reference number ofrevolutions is smaller than the recovery reference number ofrevolutions. In addition, determination as to whether or not the numberof revolutions of the engine is smaller than the engine stall referencenumber of revolutions is made in order to identify a situation where thenumber of revolutions of the engine significantly falls which may leadto engine stall in spite of resuming of fuel injection.

If eco-run ECU 230 determines that the number of revolutions of theengine is larger than the engine stall reference number of revolutions,alternator 50 is stopped. On the other hand, if eco-run ECU 230determines that the number of revolutions of the engine is smaller thanthe engine stall reference number of revolutions, it turns onelectromagnetic clutch 140 a and drives alternator 50 so that the numberof revolutions of the engine attains the target number of revolutionsduring idle.

In this manner, the rotation power of alternator 50 is transmitted tocrank shaft 110 a through pulley 160, belt 170 and pulley 140, so as torotate crank shaft 110 a. Then, if eco-run ECU 230 determines that thenumber of revolutions of the engine has attained the target number ofrevolutions during idle, alternator 50 is stopped.

If engine 110 has difficulty in returning from a fuel supply cut-offstate to operation after the processing to cut off fuel supply indeceleration, the number of revolutions of the engine is raised by meansof alternator 50, so as to prevent engine stall.

In cold start of the engine, eco-run ECU 230 controls starter 174 inaccordance with manipulation of the ignition switch by the driver, andstarter 174 starts engine 110. In addition, during normal running afterthe vehicle equipped with engine system 200 is started, eco-run ECU 230outputs signal M/G for causing alternator 50 to operate as the drivemotor to control circuit 20, and control circuit 20 drives alternator 50as the drive motor in response to signal M/G with the operationdescribed above. The torque generated by alternator 50 is transmitted todriving wheels of the vehicle equipped with engine system 200 throughpulley 160, belt 170, pulley 140, crank shaft 110 a, torque converter120, automatic transmission 130, and output shaft 130 a.

As described above, in engine system 200, control circuit 20 controllingalternator 50 is provided on the end surface of alternator 50, anddrives alternator 50 as the drive motor or the generator in accordancewith the instruction from eco-run ECU 230.

The generator-motor according to the present invention may be agenerator-motor 101 shown in FIG. 7. Referring to FIG. 7, ingenerator-motor 101, though MOS transistors Tr1 to Tr6 are connected toelectrode plates 82A to 82C, 83 by flat electrodes 91 to 96 instead ofwire bonding (W/B) in generator-motor 100 shown in FIG. 1,generator-motor 101 is otherwise the same as generator-motor 100.

Each of flat electrodes 91 to 96 is made of a copper-based material, andhas a thickness in a range from 0.1 to 2.0 mm.

Flat electrode 91 connects the source of MOS transistor Tr1 to electrodeplate 82A. Flat electrode 92 connects the source of MOS transistor Tr2to electrode plate 83. Flat electrode 93 connects the source of MOStransistor Tr3 to electrode plate 82B. Flat electrode 94 connects thesource of MOS transistor Tr4 to electrode plate 83. Flat electrode 95connects the source of MOS transistor Tr5 to electrode plate 82C. Flatelectrode 96 connects the source of MOS transistor Tr6 to electrodeplate 83.

FIG. 8A is a plan view of MOS transistor Tr1 shown in FIG. 7, while FIG.8B is a cross-sectional view of MOS transistor Tr1 and electrode plates81, 82A. In FIGS. 8A and 8B, wire GL in FIGS. 2A and 2B is replaced withflat electrode 91, and FIGS. 8A and 8B are otherwise the same as FIGS.2A and 2B.

Flat electrode 91 connects source S of MOS transistor Tr1 to electrodeplate 82A, and otherwise the description in connection with FIGS. 2A and2B also applies here.

MOS transistors Tr2 to Tr6 shown in FIG. 7 are also connected toelectrode plates 82B, 82C, 83 by flat electrodes 92 to 96 respectively,in a manner similar to MOS transistor Tr1.

In this manner, in generator-motor 101, MOS transistors Tr1 to Tr6 areconnected to electrode plates 82A, 83, 82B, 83, 82C, 83 by flatelectrodes 91 to 96, respectively.

When MOS transistors Tr1 to Tr6 are connected to electrode plates 82A,83, 82B, 83, 82C, 83 by flat electrodes 91 to 96 respectively, heatgenerated in MOS transistors Tr1 to Tr6 is dissipated through flatelectrodes 91 to 96. As a result, when MOS transistors Tr1 to Tr6 areconnected to electrode plates 82A to 82C, 83 by W/B as ingenerator-motor 100, a ratio of area of electrode plates 81, 82A to 82Cto that of MOS transistors Tr1 to Tr6 should be set to not smaller than6 in order to cool MOS transistors Tr1 to Tr6 so that temperatureincrease in MOS transistors Tr1 to Tr6 is not larger than a tolerancelimit. On the other hand, when MOS transistors Tr1 to Tr6 are connectedto electrode plates 82A to 82C, 83 by flat electrodes 91 to 96respectively as in generator-motor 101, a ratio of area of electrodeplates 81, 82A to 82C to that of MOS transistors Tr1 to Tr6 for coolingMOS transistors Tr1 to Tr6 so that temperature increase in MOStransistors Tr1 to Tr6 is not larger than a tolerance limit can be madesmaller than 6.

Accordingly, if an area for MOS transistors Tr1 to Tr6 is constant, anarea for electrode plates 81, 82A to 82C can be made smaller byconnecting MOS transistors Tr1 to Tr6 to electrode plates 82A to 82C, 83using flat electrodes 91 to 96 respectively.

Here, it goes without saying that generator-motor 101 is applicable toengine system 200.

In the present invention, alternator 50 includes a stator and a rotor,and implements a “motor” attaining a function as the motor-generator.

In addition, MOS transistors Tr1 to Tr6 constitute a “polyphaseswitching element group” controlling a current to be fed to the stator.

Moreover, in the present invention, control circuit 20, electrode plates81, 82A to 82C, 83, 84, and wires 86A to 86F constitute a “controldevice” controlling drive of the motor.

Furthermore, wires 86A to 86F constitute a “leadframe” extending fromsubstrate 84 (implemented by a ceramic substrate) to electrode plates81, 82A to 82C, 83.

According to the description above, MOS transistors Tr1 to Tr6 control acurrent fed to U-phase coil 51, V-phase coil 52 and W-phase coil 53 ofalternator 50. In the present invention, however, a switching elementsuch as an IGBT (Insulated Gate Bipolar Transistor), an NPN transistor,and the like may be employed instead of MOS transistors Tr1 to Tr6.

In addition, in the present embodiment, though the eco-run ECU and theengine ECU have separately been provided, one engine control ECU can beimplemented by integrating their functions. Moreover, the transmissionin the present embodiment is not limited to AT (what is called anautomatic transmission), and it can be implemented by a combination ofknown transmissions such as a CVT and an MT.

In the present embodiment, though a function to drive the auxiliarymachinery is attained by electromagnetic clutch 140 a, the function todrive the auxiliary machinery may not be provided for simplification ofthe system (it is not necessary to provide electromagnetic clutch 140a).

Furthermore, the present embodiment is applicable to a hybrid vehicle inwhich the motor is able to generate a large driving force in spite ofbeing adapted to an eco-run system. The present invention can beachieved even if alternator 50 is replaced by another well-knowngenerator-motor (also referred to as a motor-generator). That is, agenerator-motor capable of applying a torque necessary for driving thevehicle or starting the engine should only be selected as appropriate.

Although the present invention has been described and illustrated indetail, it is clearly understood that the same is by way of illustrationand example only and is not to be taken by way of limitation, the spiritand scope of the present invention being limited only by the terms ofthe appended claims.

INDUSTRIAL APPLICABILITY

The present invention is applicable to a compact generator-motor, or agenerator-motor provided with a control device attaining high coolingefficiency, or a generator-motor provided with a control deviceattaining shorter length and simplification of wires.

1. A generator-motor comprising: a motor including a rotor and a statorand attaining a function as a motor-generator; and a control devicearranged on an end surface of said motor so as to surround a rotationshaft of said motor and controlling drive of said motor.
 2. Thegenerator-motor according to claim 1, wherein said control deviceincludes first, second and third electrode plates arranged so as tosubstantially form a U-shape to surround the rotation shaft) of saidmotor, and a polyphase switching element group controlling a currentsupplied to said stator, said polyphase switching element group isconstituted of a plurality of arms, a number of the arms correspondingto a number of phases of said motor, and each arm constituted of firstand second switching elements, said first electrode plate is arranged ina position apart from said rotation shaft by a prescribed distance in adirection perpendicular to said rotation shaft, said second and thirdelectrode plates are arranged outside said first electrode plate, saidfirst and second switching elements are connected electrically in seriesbetween said first electrode plate and said third electrode plate, saidplurality of first switching elements are arranged on said firstelectrode plate, and said plurality of second switching elements arearranged on said second electrode plate.
 3. The generator-motoraccording to claim 2, wherein said control device further includes acontrol circuit controlling said plurality of first and second switchingelements, and said control circuit is provided on a ceramic substratearranged in a direction similar to an inplane direction of said first,second and third electrode plates in a substantially U-shaped notch. 4.The generator-motor according to claim 3, wherein said control devicefurther includes a plurality of first wires connecting said controlcircuit to said plurality of first switching elements, and a pluralityof second wires connecting said control circuit to said plurality ofsecond switching elements, said plurality of first wires are arrangedbetween said rotation shaft and said first electrode plate so as tosurround said rotation shaft, and said plurality of second wires arearranged between said rotation shaft and said first electrode plate andbetween said first electrode plate and said motor.
 5. Thegenerator-motor according to claim 4, wherein each of said plurality offirst and second switching elements includes a control terminalreceiving a control signal from said plurality of first wires or saidplurality of second wires, an input terminal receiving a direct current,and an output terminal outputting a direct current in accordance withcontrol contents by said control signal, said input terminal of saidfirst switching element is in contact with said first electrode plate,said control terminal of said first switching element is arranged on aside of said rotation shaft and connected to said first wire, saidoutput terminal of said first switching element is arranged on a side ofsaid second electrode plate and connected to said second electrodeplate, said input terminal of said second switching element is incontact with said second electrode plate, said control terminal of saidsecond switching element is arranged on a side of said rotation shaftand connected to said second wire, and said output terminal of saidsecond switching element is arranged on a side of said third electrodeplate and connected to said third electrode plate.
 6. Thegenerator-motor according to claim 2, wherein said first and secondelectrode plates are arranged in a first plane, and said third electrodeplate is arranged in a second plane different from said first plane. 7.The generator-motor according to claim 6, wherein said second plane islocated closer to said motor than said first plane is.
 8. Thegenerator-motor according to claim 2, wherein said plurality of arms(are radially arranged in the inplane direction of said first, secondand third electrode plates.
 9. The generator-motor according to claim 1,wherein said control device includes first and second electrode platesarranged so as to substantially form a U-shape to surround the rotationshaft of said motor, a polyphase switching element group controlling acurrent supplied to said stator, and a control circuit controlling saidpolyphase switching element group, and said control circuit is providedon a ceramic substrate arranged in a direction similar to an inplanedirection of said first and second electrode plates in a substantiallyU-shaped notch.
 10. The generator-motor according to claim 9, whereinsaid control circuit is resin-molded.
 11. The generator-motor accordingto claim 9, wherein said control device further includes a Zener diodeprotecting said polyphase switching element group against surge, andsaid Zener diode is arranged in said notch.
 12. The generator-motoraccording to claim 9, wherein said control device further includes acapacitive element smoothing a DC voltage from a DC power supply andsupplying the smoothed DC voltage to said polyphase switching elementgroup, and said capacitive element is arranged between said ceramicsubstrate and said second electrode plate.
 13. The generator-motoraccording to claim 9, wherein said control device further includes afield coil control unit controlling current feed to a field coildifferent from said stator, and said field coil control unit is arrangedon said ceramic substrate.
 14. The generator-motor according to claim 9,wherein a leadframe continuing to said first and second electrode platesfrom said ceramic substrate and said first and second electrode platesare arranged in an identical plane.